Epigallocatechin-3-gallate downregulates PDHA1 interfering the metabolic pathways in human herpesvirus 8 harboring primary effusion lymphoma cells

Primary effusion lymphoma (PEL) is an aggressive neoplasm correlated with human herpesvirus 8 (HHV8). Metabolic reprogramming is a hallmark of cancers. The alterations in cellular metabolism are important to the survival of HHV8 latently infected cells. Pyruvate dehydrogenase (PDH) controls the flux of metabolites between glycolysis and the tricarboxylic acid cycle (TCA cycle) and is a key enzyme in cancer metabolic reprogramming. Glutaminolysis is required for the survival of PEL cells. Glutamate dehydrogenase 1 (GDH1) converts glutamate into a-ketoglutarate supplying the TCA cycle with intermediates to support anaplerosis. Previously we have observed that epigallocatechin-3-gallate (EGCG) can induce PEL cell death and N-acetyl cysteine (NAC) attenuates EGCG induced PEL cell death. In this study, results showed that EGCG upregulated the expression of glucose transporter GLUT3, and reduced the expression of pyruvate dehydrogenase E1-alpha (PDHA1), the major regulator of PDH, and GDH1. NAC could partially reverse the effects of EGCG in PEL cells. Overexpression of PDHA1 in PEL cells or supplement of alpha-ketoglutarate attenuated EGCG induced cell death. EGCG also reduced the levels of oncometabolite D-2-hydroxyglutarate (D2HG). These results suggest that EGCG may modulate the metabolism of PEL cells leading to cell death.